I can't say that I've ever seen a relay of any type on a keyboard, but if it lets water in, it lets water out as well.
I don't know about water-soluble adhesives. I'm doubtful because ever since Freon was banned, water has been the solvent of choice for cleaning computer boards.
As SUroot said, replacement keyboards are as cheap as a cup of coffee, so there's no big risk in trying.
It should go without saying that it's not a good idea to dunk an entire laptop in water. But since that's not what we're talking about...
Once water enters a component, no amount of drying will rid the part of H20 in a timely manner. I do not know if there are relays on a KB either. I really can't tell until I see the board. Just saying, be careful.
The problem with water is it can corrode and degrade some parts. Minerals can leave deposits that can cause issues. Since a keyboard tends to be loaded with little switches, there could be a problem. And again, until I see the PCB, I cannot say.
The advice to replace the bad board with a new part is sound advice. Especially if it is cheap. Or, try to repair the KB and if you have problems, then buy a new part.
Perhaps some assemblies are cleaned with freon, but having spent a decade or more building consumer electronics, (and spending my time these days writing technical documentation) I can tell you we never used freon to clean boards. PCBs roll from the surface mount pick and place to the ovens, then the in-circuit testers, assembly and final test. No cleaning needed.
Some manufacturers might use freon, but many use products like Solvon. Some probably still use an aqueous system. We used an aqueous system to clean reworked boards. We discovered just how bad a little water can be when we reworked thousands of Megahertz Pocket Modems. Fubar was the word of the day
It really depends on the manufacturer.